【C++ Primer Plus习题】13.2

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问题:

解答:
main.cpp

#include <iostream>
#include "classic.h"

using namespace std;
void Bravo(const Cd& disk);

int main()
{
	Cd c1("Beatles", "Capitol", 14, 35.5);
	Classic c2 = Classic("Piano Sonqtq in B flat,Fantasia in c", "Alfred Brendel", "Philips", 2, 57.17);
	Cd* pcd = &c1;
	cout << "Using object directly:" << endl;
	c1.Report();
	c2.Report();
	cout << endl;
	cout << "Using type cd *pointer to objects:\n";
	pcd->Report();
	pcd = &c2;
	pcd->Report();
	cout << endl;
	cout << "Calling a function with a Cd reference argument:" << endl;
	Bravo(c1);
	Bravo(c2);
	cout << endl;
	cout << "Testing assignment: ";
	Classic copy;
	copy = c2;
	copy.Report();

	return 0;
}

void Bravo(const Cd& disk)
{
	disk.Report();
}

classic.h

#pragma once
#include <iostream>
using namespace std;

class Cd
{
private:
	char *performers;
	char *label;
	int selections;
	double playtime;
public:
	Cd(const char* s1, const char* s2, int n, double x);
	Cd(const Cd& d);
	Cd();
	virtual ~Cd();
	virtual void Report()const;
	Cd& operator=(const Cd& d);
};

class Classic :public Cd
{
private:
	char *works;
public:
	Classic(const char* s1, const char* s2, const char* s3, int n, double x);
	Classic();
	Classic(const Classic& c);
	~Classic();
	virtual void Report()const override;
	Classic& operator=(const Classic& c);
};

classic.cpp

#include "classic.h"

Cd::Cd(const char* s1, const char* s2, int n, double x)
{
	performers = new char[strlen(s1) + 1];
	strcpy_s(performers, strlen(s1) + 1, s1);
	if (strlen(s1) >= 50)performers[49] = '\0';
	else performers[strlen(s1)] = '\0';
	label = new char[strlen(s2) + 1];
	strcpy_s(label, strlen(s2) + 1, s2);
	if (strlen(s2) >= 20)label[19] = '\0';
	else label[strlen(s2)] = '\0';
	selections = n;
	playtime = x;
}
Cd::Cd(const Cd& d)
{
	performers = new char[strlen(d.performers) + 1];
	strcpy_s(performers, strlen(d.performers) + 1, d.performers);
	label = new char[strlen(d.label) + 1];
	strcpy_s(label, strlen(d.label) + 1, d.label);
	selections = d.selections;
	playtime = d.playtime;
}
Cd::Cd()
{
	performers = new char[1];
	performers[0] = '\0';
	label = new char[1];
	label[0] = '\0';
	selections = 0;
	playtime = 0;
}
Cd::~Cd()
{
	delete[] performers;
	delete[] label;
}
void Cd::Report()const
{
	cout << "Performers:" << performers << endl;
	cout << "Label:" << label << endl;
	cout << "Selecttions:" << selections << endl;
	cout << "Playtime:" << playtime << endl;
}
Cd& Cd::operator=(const Cd& d)
{
	if (this == &d)return *this;
	if (performers)delete[] performers;
	if (label)delete[] label;
	performers = new char[strlen(d.performers) + 1];
	strcpy_s(performers, strlen(d.performers) + 1, d.performers);
	label = new char[strlen(d.label) + 1];
	strcpy_s(label, strlen(d.label) + 1, d.label);
	selections = d.selections;
	playtime = d.playtime;
	return *this;
}

Classic::Classic(const char* s1, const char* s2, const char* s3, int n, double x) :Cd(s1, s2, n, x)
{
	works = new char[strlen(s3) + 1];
	strcpy_s(works, strlen(s3) + 1, s3);
	if (strlen(s3) >= 50)works[49] = '\0';
	else works[strlen(s3)] = '\0';
}
Classic::Classic() :Cd()
{
	works = new char[1];
	works[0] = '\0';
}
Classic::Classic(const Classic& c) :Cd(c)
{
	works = new char[strlen(c.works) + 1];
	strcpy_s(works, strlen(c.works) + 1, c.works);
}
Classic::~Classic()
{
	delete[] works;
}
void Classic::Report()const
{
	Cd::Report();
	cout << "Works:" << works << endl;
}
Classic& Classic::operator=(const Classic& c)
{
	if (this == &c)return *this;
	Cd::operator=(c);
	if (works)delete[] works;
	works = new char[strlen(c.works)+1];
	strcpy_s(works, strlen(c.works) + 1, c.works);
	return *this;
}